We have a pair of markets today courtesy of the lovely, Michael Bracken, who sent me the links.
Boxfire Press is an e-publisher looking for sci-fi/fantasy short stories of 2000 to 20,000 words. For these they're offering a small advance (to be negotiated) against royalties. They're also looking to start a flash fiction quarterly zine and they want flash under 500 words. Pay for these is 5cents a word with a minimum of $5 and a max of $25. They're also looking for shorts up to 20,000 words for an anthology call. The anthology theme is "There's a red scarf lying in the road. How did it get there?" This too, has a negotiable advance against royalties as payment. All submissions go through Submishmash. You can find out more about them at http://boxfirepress.com/ and at their blog http://blog.boxfirepress.com/
Aeon Press Books is an Irish publisher that's been in business for several years. They have an anthology call for horror shorts. The title is "Box of Delights", no particular theme. This is a print market paying a 10 pound advance against royalties for 2500 to 8000 words. You can find the details at http://aeonpressbooks.com/titles/box-of-delights/ Looking around the site I found that they have another anthology listed but not open, so keep your eye on the site if this market interests you.